Metal sheet drying oven



March 12, 1935. A. HO RMEL METAL SHEET DRYING OVEN I 2 Sheets-Sheet 1 Filed Jail. 5, 1954- INVENTOR BY I A? I ATTORNEY March 12,- 1935. A. HORMEL METAL SHEET DRYING OVEN 2 Sheets-Sheet 2 Filed Jan. 5, 1934 INVENTOR flaw)? 5 02/25:

Patented Mar. 12, 1935 UNITED STATES PATENT OFFICE- Tliliifillllii Applicationjanuary 3, 1934, Serial No. 705,049 scheme. (01. 34-12) This invention relates to an apparatus for dryand Fig. 7 is a sectional view on the line 7-7 of ing freshly varnished or lacquered .sheet metal Fig. 1, looking in the direction of the arrows.

plates, such as are used for the production of can The drying chamber or oven consists of an bodies and other like bodies. The object of the elongated enclosure preferably made of sheet invention is to provide a heating chamber or metal and lined with any suitable heat-insulat- 5 oven through which the plates, supported on a' 'ing material. It isprovided with side walls 10 suitable conveyor, are carried,.while an improved and a top 11, the floor 12 or other support upon heating means located in the chamber distributes which the chamber rests, constituting the bottom heated air uniformly within the chamber to of the same. At one end the chamberis closed 10 efiect rapid drying of the varnish or lacquer by the wall 13. At the other end of the chamber 10 which has been applied to the surfaces of the an entrance opening 14 is located, said opening plates. being surmounted by a hood 15 which constitutes A further object of the invention-is to provide a downward extension of the top 11 of the means for releasing the fumes oi. the varnish or chamber.

5 lacquer from within the chamber as the plates Located within the chamber and movable 15 enter and are carried for some distancewithin therethrough is a conveyor 16 which may conthe chamber. A still further object of the invensist of one or more endless chains travelling in tion is to provide a heating means so arranged the direction of the arrows in Fig. 1, .over and regulated that positive uniformity of heat sprockets 17. These chains are provided with for the entire length of the chamber is assured. means for supporting the varnished or lacquered 2 More particularly, the invention contemplates metal plates 18 on edge, such means usually cona lengthy chamber in which a conveyor carrying sisting of wire holders secured to and projecting a number of the varnished or lacquered plates from the chains, and arranged to hold the plates moves. Near the bottom of the chamber, a during the travel of the conveyor. The plates are plurality of burners, surmounted by deflector carried along on the top stretch of the chain con- 25 plates heat the air which rises through a diffusing veyor toward the end 13 of the chamber until screen and passes upwardly through the chamber the conveyor passes over the sprocket adjacent to pass through slots in an auxiliary top in the that end and the plates are then carried on the chamber to enter apassage formed between said lower stretch of the chains toward the front an auxiliary top and the top proper of the chamber. opening 14 of the chamber from where they 0' The air is then drawn through said passage by emerge in a dried condition. suction fans and forced thereby through a pas- Adjacent to the front end or entrance 14 near sage which carries'it back to a point below the the top of the chamber is provided a tubular burners where it is forced upwardly through open-ended enclosure which acts as a shield reguiatable openings adjacent the burners, to be Such plates as have just been Placed on the 35 reheated and forced into circulation through conveyor and are entering the chamber, 50 that e the chamber in the manner u described blast of air directed upwardly by fans 19 and 20, other features of the invention will be set f th located on the floor of the chamber will not hereafter; impinge against these plates. The blast of air In the accompanying drawings in which an from the fans 19 and 20 is utilized for the pur- 40 embodiment of the invention is shown, Fig. 1 is a g z g g fi fi 3 tgose paes,n ca a a,w1c aveareay een i ggigig ggg gsg fi g z g g ggi gi g g; carried through the chamber and are about to on the line of 1 lookjng in the direction emerge therefrom. This cooling treatment, conof the arrows Fig 3 a side View of a partof slstmg of the air blast directed by the fans 19 th th 1 1 tr and 20 is performed in a widened portion of the e oven 8 g 9 Yes or 9 0 chamber defined by the walls 21 which form the supply of gas used for heating; Fig. 4 1s a passages 22 through which the blast of air passes lehgitudmel seetwnal View through as indicated by the arrows in Fig. 6 to enter the of the lowe pa f the oven. showi t heatpassage 23 into which it is drawn by the fan 24 m m a s a d the m ans for re ulatin the and from which it is forced by the action of the supply of air to the cha ber; Fi 5 is a view fan. The angularly disposed bottom surfaces of one of the air valves located adjacent to the 25 of the enclosure 30 act to deflect the air blast burners; Fig. Bis asectional view on the line 66 directed by the fans 19 and 20 into the pasof Fig. 1, looking in the direction of the arrows; sages 22. 55

located co-extensively with the top plate 11 of the chamber and spaced at a distancebelow the same, is a supplemental top plate 26 which is provided for the greater part of its length with a plurality of slots 27. These slots communicate with the interior of the chamber and also with the passage 28 formed between the top plate 11 and the supplemental top plate 26.

Adjacent to the entrance end of the chamber and in the passage 28, is located a bame plate 29 having transversely arranged slots 95, said baflie plate cooperating with the top plate 11 to form sage 36 which extends along the bottom of the' casing. The end of the passage 36, toward the entrance end of the chamber is closed, as indicated at 3'7.

Located within the passage 36 are several spaced baflieplates 100 which act to impede a too rapid how of airthrough the passage. Each plate 100 is secured on a pivotal shaft 101 (Fig. 7) which has its end projecting outside of the chamber. A handle 102 is secured on the endof the shaft 101 and is adapted to bemanually moved to rock the shaft and thus position the baflle plates'at any desired inclination within the passage 36.

Provided in the top plate 38 of the air passage 36 are number of air openings 39 which are regulatable in size by means-of the angular plates 40 and 41 constituting valves. The plates 41 have their ends 42 bent laterally to overlap the ends of the plates 40. Said plates 40 and 41 may be brought toward, or separated from one another by means of the adjusting screws 43 so that the openings 39 between the plates 40 and 41 are regulatable in size.

Located between the numerous sets of the plates 40 and 41 are heating members consisting of gas burner pipes 44, perforated in their upper faces to form jets from which gas emanating from the perforations can be ignited. These various burners 44 extend inwardly from manifold pipes 45. Each manifold pipe v45 is connected to a group of burner pipes 44 so that a number of the manifold pipes 45 are employed. Each manifold pipe 45 is connected to a supply pipe 46 which connects to a gas main 47. Each of the supply pipes 46 is provided with shut-oi! valves 48 and 49 between which is located athermostatlc control device 50 arranged to shut off or decrease the gas supply to the particular manifold to which pipe 46 -is connected. The thermostatic control 50 for each of the pipes 46 is governed by the temperature in the particular part of the chamber where it is located. With the arrangement just described, the temperature throughout the lengthy heating chamber may be constantly maintained uniform since each section of the chamber defined by a separate manifold pipe 45 is independently controlled by its own thermostatic control. Itis, therefore, possible for the first section of the chamber, at the left of Fig. 2, for example, to beconstantly maintained at the same temperature as'the extreme end section, located at the right of Figs. 1 and 2. Should the use of the thermostatic control in any of the sections of the chamber be found undesirable at any time, the valves 48 and 49 may be closed and a valve 51 located in a bypass'52 in the pipe 46 is opened which permits the gas flow to pass around the thermostatic control, and enter the manifold 45.

A deflector plate 53 supported by the brackets 96 from cross-bars 97 is located over each of the burner pipes- 44, these plates 53 deflecting the heated air in the manner shown by the arrows in Fig. 4. The heated air rises and passes through a perforated plate orscreen 54 mounted over the burners and deflector plates 53. The screen 54 difluses or breaks up the air flow which then passes upwardly through the heating chamber impinging against the varnished or lacquered plates carried on the conveyor and acting to dry the same. The heated air upon rising toward the top of the chamber, passes upwardly through the slots 27 in the supplemental top plate 26 and enters into the passage 28,- as shown in Fig. l, where it is drawn by the fans 34 toward the end of the chamber and forced downwardly through the passage 35 into the lower longitudinal passage 36 and upthrough the air openings '39 to be reheated by the burners 44 to again pass upward through the chamber, as just described. Adjacent to the fans 34 in the top plate 11 is prov vided an air, opening 55 in which is located a valve 56 permitting the entry of a supply of fresh air to the fans-34 in regulatable quantity.

Briefly, the operation of the device is as follows: The varnished or lacquered plates 18 are placed on the conveyor at the entrance opening .14 there- 'of and are moved through the chamber on the upper stretch of the chain conveyor 16. The

fumes from the freshly applied varnish or lacquer pass upwardly under the hood 15 into the con-- tracted portion 56 of the passage 28 and are drawn into the exhaust passage'23 by the fan or.

blower 24. A valve'5'1 is located in the passage 58 to control the size of the passage. I

As the plates are moved on the conveyor toward the right in Fig. 1, they are carried through the tubular enclosure 30 and finally pass out of the same. Any additional fumes emanating from the varnish can pass upwardly through the slots 2'! in the supplemental top plate 26 and pass through the transverse slots 95 in the banle plate 29 to enter the narrow passage 31 to be drawn into the exhaust passage 23 by the action of the blower 24.

When the plates pass beyond the inner end of the baffle plate 29, the fumes emanating therefrom are negligible and the plates continue their movement toward the inner end of the chamber, receiving a constant flow of hot air from the burners 44 over which they pass while being moved by the conveyor. When the plates reach the inner end of the chamber where the chain conveyor passes 'over the inner sprockets, the plates then depend from the lower stretch of the chainandare carried toward the left in Fig. 1 on their movement to the opening 14. When they reach a point below ,the enclosure 30, they receive a cooling the passage having air-diflusing plate located above the heating means, means for directing an air blast against the bottom portion of the conveyor and means for shielding the top portion of the conveyor from said air blast.

2, An apparatus of the character described comprising, an elongated heating chamber having an entrance opening at one of its ends and closed at its other end, a conveyor movable therein, heating means comprising a plurality of spaced burners arranged along the bottom of the chamber, a continuous air passage located below the heating means and extending along the back end and along the top of the chamber, said passage having apertures in its top portion communicating with the interior of'the chamber, the passage having valve-regulated openings in its bottom portion adjacent to the heating means, means for forcing air from the top portion of the passage through the end portion and down to the bottom portion of said passage, a fresh-air supply for the top portion of the passage and means for regulating said supply, an air-diflusing plate loca above the heating means. means located near the entrance opening for directing an air blast against the bottom portion of the conveyor and means for shielding the top portion of the conveyor from said air blast.

3. An apparatus of the character described comprising, a heating chamber, a conveyor movable therethrough heating means arranged along the bottom of the chamber, said heating means comprising spaced burner pipes with overlying plates to be heated thereby, a lower air passage located below the heating means, said passage being provided with vents located between the plates, means for regulating the size of said vents, an upper air e, a connecting passage between the upper and lower passage, and a blower operative to force air from the upper passage to the lower passage and through the vents formed there 4. An apparatus of the class described comprising, an elongated heating chamber having an entrance opening at one of its ends and closed at its other end, a conveyor movable therethrough, heating means arranged along the bot tom of the chamber and consisting of spaced burner pipes with overlying plates to be heated,

thereby, a continuous air passage located below means and extending along the back end of the chamber and along the top of the same, the upper portion of said passage being provided with vents in the form of transverse slots, means for contracting said slots to regulate the width of the same, means for forcing air from the top portion of the passage -down through the end portion to reach the bottom portion thereof, and means adjacent the entrance opening of the chamber for directing anair blast. against those plates on the conveyor which have been carried through the chamber and are on their way to the entrance opening.

5. An apparatus of the character described comprising, a chamber. a conveyor movable therethrough, means for heating and means for circulating air within'the chamber; the chamber having anopening at one of its ends through which articles are placed the conveyor, means located within the chamber and below the conveyor for directing an air blast upwardly against those articles which are located on the lower run of the conveyor and which are being moved toward the opening in the chamber, a tubular, open-ended enclosure located above the air-blast directing means and enclosing the upper run of the conveyor, to shield from the air blast articles ward the interior of the chamber by the conveyor, and air passages extending upwardly on opposite sides or the enclosure to carry the air blast past the same and out of the chamber.

on and removed from which are being moved to-- 

